Base64 string padding char seems to trip up parser

[alexswan10k]

Description

For base 64 encoded strings, they are often padded with an = character. This seems to break the parser and return None for a query string parameter with padding.

Workaround

String.replace ("=", "@") //or some other character that isn't in the standard base64 set and is allowed in a query param
//https://en.wikipedia.org/wiki/Base64

Repro code

let route = s "someRoute"  <?> stringParam "data"

Then run any query string with padding. For example:
domain.com/someRoute?data=YQ==
where data is "a" in this context.

Expected and actual results

• Expected
  ** data = Some "YQ=="
• Actual
  ** data = None

Related information

• elmish version: Fable.Elmish (3.0.6)
• fable-compiler version: 2.4.11
• fable-core version:Fable.Core (3.1.3)
• Operating system: Windows 10

Hopefully this is quite clear. I imagine it is probably due to the parser maybe splits on = rather than parse based on previous context - eg a parameter can only start with ? or & and is followed by an =.

I know that base64 isnt that common, but its handy for passing around complex serialised graphs compactly. Tokens are also also sometimes sent back to a client this way, although they do use hashtag navigation.

Let me know if anything else is needed.

[et1975]

thanks, I'll take a look.

[et1975]

So it seems you should URL encode the base64 strings precisely because it can contain special characters.

[alexswan10k]

Ah yes indeed. Sorry I should have looked this up before opening - I actually tried this myself and had a heap of other problems so assumed this wouldn't work. I was under the impression an equivalent OAUTH example i had does not urlencode, but perhaps that was an incorrect assumption.

As it stands I actually found a totally different way to handle my issue so happy to close this.